Repeated platelet-rich plasma injections improve erectile dysfunction in a rat model of hyperhomocysteinemia.

ABSTRACT: Platelet-rich plasma (PRP) shows promise as a regenerative modality for mild-to-moderate erectile dysfunction (ED). However, its efficacy in treating severe ED remains unknown. Blood samples from 8-week-old male rats were used to prepare PRP through a two-step centrifugation procedure, followed by chitosan activation and freeze‒thaw cycle. A hyperhomocysteinemia (HHcy)-related ED model was established using a methionine-enriched diet, and an apomorphine (APO) test was conducted during the 4th week. APO-negative rats were divided into two groups and were injected with PRP or saline every 2 weeks. Erectile function and histological analyses of the corpus cavernosum were performed during the 16th week. The results revealed that erectile function was significantly impaired in rats with HHcy-related ED compared to that in age-matched rats but was improved by repeated PRP injections. Immunofluorescence staining revealed a reduction in reactive oxygen species and additional benefits on the recovery of structures within the corpus cavernosum in rats that received PRP treatment compared to those in the saline-injected control group. Therefore, PRP could enhance functional and structural recovery in a severe HHcy-related ED model. A notable strength of the present study lies in the use of a repeated intracavernous injection method, mirroring protocols used in human studies, which offers more reliable results for translating the findings to humans.

Inhibition of FoxO1 alleviates polycystic ovarian syndrome by reducing inflammation and the immune response.

The aim of this study was to explore the role of forkhead box transcription Factor O1 (FoxO1) in chronic inflammation in polycystic ovary syndrome (PCOS). A PCOS rat model was constructed as an in vivo model by letrozole induction, and granulosa cells (GCs) from PCOS rats were isolated and cultured as an in vitro cellular model. FoxO1 was knocked down by shRNA and siRNA in the PCOS rat model and GCs model, respectively. H&E staining was conducted to evaluate the effect of FoxO1 inhibition on ovarian pathology and dysfunction in PCOS rats. The levels of inflammatory cytokines in the ovaries and uterus of PCOS rats and in GCs were assessed by ELISA. Flow cytometry was used to evaluate the changes in the contents of neutrophils and macrophages in the peripheral blood and spleen of PCOS rats. CCK-8 assays and Annexin V-FITC/PI staining were performed to evaluate the proliferation and apoptosis of GCs. The expression of genes and proteins related to the TLR4/NF-κB/NLRP3 pathway in GCs was determined by RT-qPCR and Western blotting. The results indicated that FoxO1 was highly expressed in PCOS rat model. Inhibition of FoxO1 significantly mitigated the pathological changes and dysfunction in the ovaries of PCOS rats while also suppressing inflammation and fibrosis in the ovaries and uterus. Moreover, knocking down FoxO1 facilitated the restoration of the normal ratio of neutrophils and macrophages in the peripheral blood and spleen of PCOS rats and promoted M2 polarization of macrophages. Additionally, inhibition of FoxO1 promoted the proliferation of GCs and inhibited the inflammatory response in GCs. Furthermore, FoxO1 knockdown inhibited the activation of the NF-κB pathway and the formation of the NLRP3 inflammasome in GCs. In conclusion, inhibition of FoxO1 can alleviate PCOS by inhibiting the TLR4/NF-κB/NLRP3 pathway to reduce inflammation and the immune response.

Effects of microplastics/nanoplastics on Vallisneria natans roots and sediment: Size effect, enzymology, and microbial communities.

Microplastics/nanoplastics (MNPs) pollution in different environmental media and its adverse effects on organisms have received increasing attention from researchers. This paper compares the effects of natural concentrations of three different sizes (20 nm, 200 nm, and 2 µm) of MNPs on Vallisneria natans and sediments. MNPs with smaller sizes adhere more readily to V. natans roots, further promoting root elongation. In addition, the larger the particle size of MNPs, the higher the reactive oxygen species level in the roots, and the malondialdehyde level increased accordingly. In the sediment, 20 nm, and 200 nm MNPs increased the activity of related enzymes, including acid phosphatase, urease, and nitrate reductase. In addition, the dehydrogenase content in the treated sediments increased, and the content changes were positively correlated with the size of MNPs. Changes in microorganisms were only observed on the root surface. The addition of MNPs reduced the abundance of Proteobacteria and increased the abundance of Chloroflexi. In addition, at the class level of species composition on the root surface, the abundance of Gammaproteobacteria under the 20 nm, 200 nm, and 2 µm MNP treatments decreased by 21.19%, 16.14%, and 17.03%, respectively, compared with the control group, while the abundance of Anaerolineae increased by 44.63%, 26.31%, and 62.52%, respectively. These findings enhance the understanding of the size effects of MNPs on the roots of submerged plants and sediment.

Effects of eutrophic water with ammonium chloride, urea, potassium dihydrogen phosphate and sodium-ß-glycerophosphate on Myriophyllum verticillatum and epiphytic bacteria.

With the rapid development of industry and agriculture, excessive nitrogen and phosphorus released into natural surface water have caused eutrophication. Applying submerged plants to manage eutrophic water has attracted widespread attention. However, there are limited studies on the effects of different nitrogen and phosphorus in the water environment on submerged plants and their epiphytic biofilm. Therefore, this paper investigated the effects of eutrophic water with ammonium chloride (IN), urea (ON), potassium dihydrogen phosphate (IP), and sodium-ß-glycerophosphate (OP) on Myriophyllum verticillatum and epiphytic biofilms. The results showed that Myriophyllum verticillatum exhibited a good purification effect on the eutrophic water with inorganic phosphorus, the removal rates of IP were 68.0%, and the plants grew best in this condition. The fresh weight of the IN group and ON group increased by 12.24% and 7.12%, and the shoot length of the IN group and the ON group increased by 17.71% and 8.33%; the fresh weight of the IP group and OP group increased by 19.19% and 10.83%, the shoot length of the IP group and the OP group increased by 21.09% and 18.23%. In addition, the enzyme activities of superoxide dismutase, catalase, nitrate reductase, and acid phosphatase in plant leaves were significantly changed in eutrophic water with different forms of nitrogen and phosphorus. Finally, the analysis of the epiphytic bacteria showed that different forms of nitrogen and phosphorus nutrients could significantly alter the abundance and structure of microorganisms and microbial metabolism also had significant changes. This study provides a new theoretical basis for evaluating the removal of different forms of nitrogen and phosphorus by Myriophyllum verticillatum, and it also provides new insights for the subsequent engineering of epiphytic microorganisms to improve the capability of submerged plants to treat eutrophic water.

Bibliometric analysis of 100 top cited articles of heart failure-associated diseases in combination with machine learning.

Objective: The aim of this paper is to analyze the application of machine learning in heart failure-associated diseases using bibliometric methods and to provide a dynamic and longitudinal bibliometric analysis of heart failure-related machine learning publications. Materials and methods: Web of Science was screened to gather the articles for the study. Based on bibliometric indicators, a search strategy was developed to screen the title for eligibility. Intuitive data analysis was employed to analyze the top-100 cited articles and VOSViewer was used to analyze the relevance and impact of all articles. The two analysis methods were then compared to get conclusions. Results: The search identified 3,312 articles. In the end, 2,392 papers were included in the study, which were published between 1985 and 2023. All articles were analyzed using VOSViewer. Key points of the analysis included the co-authorship map of authors, countries and organizations, the citation map of journal and documents and a visualization of keyword co-occurrence analysis. Among these 100 top-cited papers, with a mean of 122.9 citations, the most-cited article had 1,189, and the least cited article had 47. Harvard University and the University of California topped the list among all institutes with 10 papers each. More than one-ninth of the authors of these 100 top-cited papers wrote three or more articles. The 100 articles came from 49 journals. The articles were divided into seven areas according to the type of machine learning approach employed: Support Vector Machines, Convolutional Neural Networks, Logistic Regression, Recurrent Neural Networks, Random Forest, Naive Bayes, and Decision Tree. Support Vector Machines were the most popular method. Conclusions: This analysis provides a comprehensive overview of the artificial intelligence (AI)-related research conducted in the field of heart failure, which helps healthcare institutions and researchers better understand the prospects of AI in heart failure and formulate more scientific and effective research plans. In addition, our bibliometric evaluation can assist healthcare institutions and researchers in determining the advantages, sustainability, risks, and potential impacts of AI technology in heart failure.

Distribution and potential ecological risks of microplastics in Zhushan Bay, China.

The interaction between microplastics (MPs) and microorganisms may alter the distribution of antibiotic resistance genes (ARGs) in water and increase the ecological risk of drinking water sources. To investigate the characteristics of MPs geographical distribution and its potential ecological risk in typical urban water, this study was conducted in Zhushan Bay, and we carried out a combination of tests to analyze the distribution of MPs and the migration changes of their surface microbial community composition and ARGs in different media by 16S rRNA gene high-throughput sequencing, non-targeted metabolomics and qPCR genomics in the near-shore (I), middle area (Ⅱ) and near-lake (Ⅲ) of Zhushan Bay. The results showed that MPs in fibrous form were dominant in the aquatic environment of Zhushan Bay; Polyurethane (PU) and Silicone were the main MPs types in Zhushan Bay. The abundance of MPs in the water of Zhushan Bay was winter > summer > autumn > spring; and in the sediment was winter > summer > autumn > spring, respectively. The distribution results of MPs in geographical location are as follows: In the water I > â…¡ > â…¢, sediment exhibited Ⅱ > â…¢ > I. The results indicate that physicochemical factors will affect the geographical distribution of MPs and their surface microbial community composition in the aquatic environment of Zhushan Bay. More cooperative behaviors and increased metabolically important pathways occurred in the microbial network on water-MPs compared to sediment-MPs. However, the microbial community in the sediment-MPs was more stable and had higher abundance of mobile genetic elements (MGEs). A total of 362 differential metabolites were detected, of which 193 were up-regulated and 19 down-regulated differential metabolites. blaTEM, Sul, and inti1 were prevalent in both the water and sediments of Zhushan Bay. Sul1 was most contaminated in ARGs. This study provides the latest field data and insights into MPs pollution in key aquatic environments.

Federal learning edge network based sentiment analysis combating global COVID-19.

As one of the important research topics in the field of natural language processing, sentiment analysis aims to analyze web data related to COVID-19, e.g., supporting China government agencies combating COVID-19. There are popular sentiment analysis models based on deep learning techniques, but their performance is limited by the size and distribution of the dataset. In this study, we propose a model based on a federal learning framework with Bert and multi-scale convolutional neural network (Fed_BERT_MSCNN), which contains a Bidirectional Encoder Representations from Transformer modules and a multi-scale convolution layer. The federal learning framework contains a central server and local deep learning machines that train local datasets. Parameter communications were processed through edge networks. The weighted average of each participant's model parameters was communicated in the edge network for final utilization. The proposed federal network not only solves the problem of insufficient data, but also ensures the data privacy of the social platform during the training process and improve the communication efficiency. In the experiment, we used datasets of six social platforms, and used accuracy and F1-score as evaluation criteria to conduct comparative studies. The performance of the proposed Fed_BERT_MSCNN model was generally superior than the existing models in the literature.

Mechanism of cyanobacterial bloom control by magnetic lanthanum-based material.

In this study, the mechanism of magnetic P-inactivating material on cyanobacterial bloom control was investigated by adding magnetic lanthanum-based material (MLC-10) in different stages of cyanobacterial growth during a 30-day cultivation experiment. The results showed that adding MLC-10 could rapidly reduce the available phosphorus, achieve phosphorus limitation in water body, and inhibit cyanobacterial blooms in the water column. In particular, the addition of MLC-10 at the early stage of cyanobacterial growth (day 0) achieved 97.5% bloom control. Additionally, cyanobacteria was captured and precipitated by MLC-10, and the floating ability of cyanobacteria was reduced. The results of antioxidant enzyme activities showed that adding MLC-10 may cause damage to the activity of cyanobacteria and induce stress response of cyanobacterial cells, which increased with increasing of exposure time. Besides, the results of metabolomics further suggested that adding MLC-10 mainly affected the amino acid metabolism, lipid metabolism and tRNA synthesis of cyanobacteria, which lead to the damage to cells' activities and membrane transport. These results provide insight into the mechanism of MLC-10 as a magnetic P-inactivating material on cyanobacterial bloom control.

Potential mechanism of humic acid attenuating toxicity of Pb2+ and Cd2+ in Vallisneria natans.

Humic substances are widely present in aquatic environments. Due to the high affinity of humic substances for metals, the interactions have been particularly studied. To assess the effect of humic acid (HA) on submerged macrophytes and biofilms exposed to heavy metal stress, Vallisneria natans was exposed to solutions containing different concentrations of HA (0.5-2.0 mg·L-1), Pb2+ (1 mg·L-1) and Cd2+ (1 mg·L-1). Results suggested that HA positively affected the plant growth and alleviated toxicity by complexing with metals. HA increased the accumulation of metals in plant tissues and effectively induced antioxidant responses and protein synthesis. It was also noted that the exposure of HA and metals promoted the abundance and altered the structure of microbial communities in biofilms. Moreover, the positive effects of HA were considered to be related to the expression of related genes resulting from altered DNA methylation levels, which were mainly reflected in the altered type of demethylation. These results demonstrate that HA has a protective effect against heavy metal stress in Vallisneria natans by inducing effective defense mechanisms, altering biofilms and DNA methylation patterns in aquatic ecosystems.

Selection of fertilization strategies for different sperm parameters in vitro fertilization.

Background: Fertilization is a prerequisite for successful human reproduction. The choice of clinical fertilization strategy is crucial and directly affects clinical outcomes. This study analyzes the most appropriate assisted reproductive technology (ART) strategy based on sperm parameters. Methods: Semen samples were divided into six groups based on semen progressive motility (PR) and semen density (SD): HMLD (high motility-low density) (PR ≥32% and sperm density <15×106/mL, n=60), HMID (high motility-intermediate density) (PR ≥32% and 15×106/mL ≤ SD <30×106/mL, n=106), HMHD (high motility-high density) (PR ≥32% and SD ≥30×106/mL, n=1,009), LMLD (low motility-low density) (PR <32% and SD <15×106/mL, n=99), LMID (low motility-intermediate density) (PR <32% and 15×106/mL ≤ SD <30×106/mL, n=77), and LMHD (low motility-high density) (PR <32% and SD ≥30×106/mL, n=164). We analyzed hyaluronic acid binding (HAB) assay and acrosin activity, along with fertilization, embryonic development, and pregnancy outcomes, to demonstrate the correlation of sperm parameters with fertilization function. Results: In the PR <32% groups, the rate of intracytoplasmic sperm injection (ICSI) treatment decreased with increasing sperm concentration. Specifically, approximately 10% of in vitro fertilization (IVF) treatment cycles required a rescue ICSI when sperm PR was <32% accompanied by SD ≥15×106/mL and PR ≥32% accompanied by SD <30×106/mL, which was significantly higher than HMHD group, P<0.001. Sperm acrosin activity and HAB ability were significantly higher in the groups with good sperm parameters, P<0.05. Conclusions: The findings of this study suggest, fertilization ability of sperm is closely related to sperm motility and density. In clinical practice, IVF strategies should be refined based on male sperm parameters.

Combined toxic effects of enrofloxacin and microplastics on submerged plants and epiphytic biofilms in high nitrogen and phosphorus waters.

With the wide application of plastic products, microplastic pollution has become a major environmental issue of global concern. Microplastics in aquatic environments can interact with organic pollutants, causing a combined effect on submerged macrophytes. This study investigated the response mechanisms of the submerged plant Myriophyllum verticillatum and epiphytic biofilm to the antibiotic enrofloxacin, microplastics, and their combined exposure in a high nitrogen and phosphorus environment. The results indicated that Myriophyllum verticillatum was not sensitive to enrofloxacin of 1 mg L-1, while 10 and 50 mg L-1 enrofloxacin inhibited the uptake of nitrogen and phosphorus by the plants, as well as triggered oxidative stress in the plant leaves, causing irreversible damage to the plant cells. In addition, enrofloxacin altered the structure of the leaf epiphytic biofilm community. Interestingly, 1, 5, and 20 mg L-1 microplastics had no significant effect on the plant, while they facilitated the aggregation of microorganisms, increasing the abundance of the leaf epiphyte biofilm. The combination of enrofloxacin and microplastics induced a synergistic effect on Myriophyllum verticillatum. Specifically, the rate of nitrogen and phosphorus uptake by the plant was reduced, the content of photosynthetic pigments decreased, and antioxidant enzyme activity was further increased. In addition, the diversity of the leaf epiphytic biofilm community was similar to the single enrofloxacin exposure. These results demonstrated the differences between single and combined exposures and provided a new theoretical basis to evaluate the harmful effects of enrofloxacin and microplastics on submerged macrophytes.

Response of submerged macrophytes and leaf biofilms to different concentrations of oxytetracycline and sulfadiazine.

Oxytetracycline and sulfadiazine were widely used and they entered the environment through various channels such as domestic sewage, medical wastewater and agricultural wastewater, causing significant ecological risk. To determine the effects of different antibiotic concentrations on submerged macrophytes, Vallisneria natans was exposed to solutions containing different concentrations of oxytetracycline and sulfadiazine (0.1 mg/L、1 mg/L、10 mg/L、50 mg/L). After 20-days exposure, we found that 10 mg/L groups had a significant effect on Vallisneria natans. Under high antibiotic concentrations, the growth of Vallisneria natans was inhibited, chloroplasts were deformed, the chlorophyll content was reduced, and antioxidant enzyme activities, such as superoxide dismutase and glutathione, were increased. There was no significant difference between the control group and groups with low antibiotic concentrations (≤1 mg/L). The N-acyl-l-homoserine lactone concentration tended to increase with increasing antibiotic concentrations. The presence of antibiotics also affected the microbial community structure of biofilms on the submerged macrophytes. For example, the higher the concentration of antibiotics, the higher the proportion of Proteobacteria. These results suggest that high concentrations of oxytetracycline and sulfadiazine can disrupt homeostasis, induce effective Vallisneria natans defense mechanisms and alter biofilms in aquatic ecosystems.

Shift of calcium-induced Microcystis aeruginosa colony formation mechanism: From cell adhesion to cell division.

Colony formation is an essential stage of cyanobacterial blooms. High calcium concentration can promote Microcystis aeruginosa aggregation behavior, but the mechanism of colony formation caused by calcium has rarely been reported. In this study, high calcium-induced colony formation was identified as a shift from cell adhesion to cell division, rather than only cell adhesion as previously thought. Algae responded to this calcium-induced environmental pressure by aggregating and forming colonies. Algal cells initially secreted large quantities of extracellular polysaccharides (EPS) and rapidly aggregated by cell adhesion. The highest aggregation proportion was up to 68.93%. However, high calcium concentrations cannot completely inhibit algal cell growth, but only delay the algae into the rapid growth phase. With adaption to calcium and existing high EPS content, the daughter cells reduced EPS synthesis and the aggregation proportion decreased. The increasing growth rate was also responsible for the decreased xylose content in EPS. The mechanism of colony formation changed to cell division. The downregulation of genes related to EPS secretion also supported this hypothesis. Overall, these results can benefit for our understanding of cyanobacterial bloom formation.

Fertility Outcome and Safety of Ethiodized Poppy Seed Oil for Hysterosalpingography in 1,053 Infertile Patients: A Real-World Study.

Objective: Ethiodized poppy seed oil for hysterosalpingography (HSG) is reported to display some therapeutic effect on infertility, but big a sample-size study under real clinical settings is still lacking to verify the speculation. Thus, this real-world study enrolled 1,053 infertile patients who underwent ethiodized poppy seed oil-based HSG to explore its fertility enhancement value. Method: A total of 1,053 infertile patients who underwent HSG using ethiodized poppy seed oil as the contrast medium were retrospectively analyzed. The live birth rate and 3-, 6-, 12-month and total pregnancy rate were retrieved. Besides, adverse events during and after HSG were recorded. Results: The 3-, 6-, 12-month and total pregnancy rate was 22, 36.8, 50, and 53.8%, respectively. The total live birth rate was 42.7%. Sub-group analyses showed that pregnancy rate was 53.7, 53.8, 54.1, and 62.4% in subgroups of primary infertility patients, secondary infertility patients, infertility patients with fallopian tube disease, and infertility patients with unknown cause, respectively. Meanwhile the live birth rate was 44.3, 41.3, 41.5, and 59.2% in these subgroups, separately. Multivariate logistic regression analysis disclosed that BMI ≥ 24 kg/m2, history of dysmenorrhea, and abnormity of sperm count or motility-related infertility were independently correlated with reduced pregnancy rate and livebirth rate (All Ps < 0.05). Adverse events mainly included pain (20.6%) and interstitial reflux (7.9%), which were mild and tolerable. Conclusion: Ethiodized poppy seed oil for HSG discloses a satisfying fertility outcome with a tolerable safety profile in infertile patients; meanwhile, this effect might be influenced by BMI, history of dysmenorrhea, and paternal abnormity of sperm.

Single and combined toxicity effects of nanoplastics and bisphenol F on submerged the macrophyte Hydrilla verticillata.

Nano- and microplastics pose severe risks to the ecological environment. Nanoplastics (NPs) not only directly affect aquatic organisms, but also adsorb to other pollutants, resulting in compound pollution. Bisphenol F (BPF), an endocrine-disrupting chemical, is increasingly replacing bisphenol A (BPA) and is therefore widely distributed in the environment. In this study, the toxic effects of polystyrene nanoplastics (PS-NPs) and BPF and their combined exposure on the submerged macrophytes Hydrilla verticillata (H. verticillata) and leaf biofilms, were investigated. Results showed that 10 mg/L PS-NPs and combined exposure to 10 mg/L PS-NPs and 10 mg/L BPF significantly decreased the relative growth rate and chlorophyll content of H. verticillata, whereas BPF exposure alone had no impact on the growth and the contents of photosynthetic pigments in H. verticillata. Individual and combined exposure to PS-NPs and BPF can trigger antioxidant responses such as increased activities of superoxide dismutase, peroxidase, and malondialdehyde, as well as higher levels of glutathione S-transferase and glutathione and decreased catalase activity. The results of the scanning electron microscopy (SEM) showed that the nanoplastics particles were adsorbed on the surface of plant leaves, explaining their toxic effects, whereas BPF increases the sorption of PS-NPs on the surface of H. verticillata, potentially leading to PS-NPs enrichment in the food chain. The diversity and richness of the microbial community were altered by exposure to PS-NPs and BPF individually and in combination. The current study is the first to assess the effects of PS-NPs and BPF exposure on the growth, physiological characteristics, and leaf biofilm properties of submerged macrophytes.

Effect of submerged plant coverage on phytoplankton community dynamics and photosynthetic activity in situ.

Restoration of submerged plants in eutrophic lakes can reduce nutrients and phytoplankton biomass in the water body. However, the effect of submerged plants on phytoplankton communities and their photosynthetic activity in situ are still poorly understood. Here, we studied the response of phytoplankton community structure and fluorescence parameters to different submerged plants coverage, the relationship of phytoplankton community and fluorescence parameters with submerged plants coverage and water physicochemical parameters were analysed in sampling area of Hangzhou West Lakes. The results showed that the coverage and biomass of submerged plants were negatively correlated with nitrogen and phosphorus contents in water body but positively correlated with total phenol content. The ratio of nitrogen to phosphorus in the study site changed greatly (32.25-124.54). In spring and summer, Oscillatoria and Leptolyngbya (Cyanophyta) were the dominant species, while in autumn and winter, the dominant species were Cyclotella (Chlorophyta), and Melosira and Cymbella (Bacillariophyta). Compared with Chlorophyta and Bacillariophyta, fluorescence parameters of Cyanophyta were more sensitive to total phosphorus, N:P ratio, total phenols, pH, and electric conductivity. Fluorescence parameters of Chlorophyta and Bacillariophyta were only affected by underwater light. Total phosphorus (TP) and N:P had a negative effect on the maximum photochemical electron yield of Cyanophyta. Furthermore, Cyanophyta was inhibited by total phenols from submerged plants. When phytoplankton were under stress, photochemical electron yield decreased significantly, whereas non-photochemical quenching increased. The structural equation model showed that the coverage of submerged plants might indirectly affect the fluorescence parameters of Cyanophyta by affecting nitrogen, phosphorus, and total phenol contents in the water body. These findings contribute to the understanding of the mechanisms underlying the impact of submerged plant restoration on phytoplankton community dynamics in subtropical eutrophic shallow lakes and provide a theoretical basis for the management of lakes.

[Spatial Distribution Characteristics of Phosphorus Fractions and Release Risk in Sediments of Honghu International Importance Wetland].

According to a spatial distribution analysis of phosphorus in sediments from Honghu Wetland, it was found that TP content in sediments at the mouth of Honghu Lake was 781.31-1955.84 mg·kg-1 and the average value was(1287.21±437.28)mg·kg-1. TP content in sediments in the open water area was 438.33-1554.04 mg·kg-1, with an average value of(718.10±238.15)mg·kg-1. The TP content of sediments in lake inlet was significantly higher than that of sediments in the open water area(P<0.05), and that in the enclosed aquaculture was higher than in the open water area, although no significant difference was observed (P>0.05). The TP content of sediments to the northwest and northeast of Honghu Lake was higher than that to the southwest of Honghu Lake, and the TP content of sediments in The Four-lake main canal was significantly higher than that of Luoshan main canal(P<0.05). The phosphorus input in the Four-lake main canal may be the main source of phosphorus in Honghu Lake sediments. The phosphorus fraction composition in sediments from different sampling sites were significantly different. Fe/Al-P and Ca-P were the main forms of phosphorus in sediments from the lake inlet, while OP and Ca-P were the main forms of phosphorus in sediments from the open water area. The variation in spatial phosphorus form composition was related to the influence of human activity and the distribution of aquatic plants. Fe/Al-P and OP contents were used to estimate the content of biological available phosphorus (BAP) in evaluated sediments, and the proportion of BAP in TP was used to estimate the risk of phosphorus release in Honghu sediments. BAP/TP was 39.8%-69%, with an average of(56.5±7.23)%, indicating a high risk of phosphorus release. OP and BAP were significantly correlated with TP in overlying water(P<0.01), and the correlation between BAP and phosphate in the overlying water was the highest. The results showed that phosphorus concentration in the overlying water may be related to the release of Fe/Al-P and OP into water bodies.

The chromosome-level Stevia genome provides insights into steviol glycoside biosynthesis.

Stevia (Stevia rebaudiana Bertoni) is well known for its very sweet steviol glycosides (SGs) consisting of a common tetracyclic diterpenoid steviol backbone and a variable glycone. Steviol glycosides are 150-300 times sweeter than sucrose and are used as natural zero-calorie sweeteners. However, the most promising compounds are biosynthesized in small amounts. Based on Illumina, PacBio, and Hi-C sequencing, we constructed a chromosome-level assembly of Stevia covering 1416 Mb with a contig N50 value of 616.85 kb and a scaffold N50 value of 106.55 Mb. More than four-fifths of the Stevia genome consisted of repetitive elements. We annotated 44,143 high-confidence protein-coding genes in the high-quality genome. Genome evolution analysis suggested that Stevia and sunflower diverged ~29.4 million years ago (Mya), shortly after the whole-genome duplication (WGD) event (WGD-2, ~32.1 Mya) that occurred in their common ancestor. Comparative genomic analysis revealed that the expanded genes in Stevia were mainly enriched for biosynthesis of specialized metabolites, especially biosynthesis of terpenoid backbones, and for further oxidation and glycosylation of these compounds. We further identified all candidate genes involved in SG biosynthesis. Collectively, our current findings on the Stevia reference genome will be very helpful for dissecting the evolutionary history of Stevia and for discovering novel genes contributing to SG biosynthesis and other important agronomic traits in future breeding programs.

The changing characteristics of phytoplankton community and biomass in subtropical shallow lakes: Coupling effects of land use patterns and lake morphology.

The community composition and biomass of phytoplankton in shallow lakes are impacted by many environmental factors including water quality physicochemical parameters, land use in the watershed, and lake morphology. However, few studies have simultaneously evaluated the relative importance of these factors on the effect of community composition and biomass of phytoplankton. The relative importance of the water quality physicochemical parameters (water temperature [WT], total nitrogen [TN], total phosphorus [TP], pH, dissolved oxygen [DO], electrical conductivity [EC], turbidity and Secchi depth [SD]), land use (built-up land, farmland, waters, forest, grassland, and unused land) in the watershed, and lake morphology (area and depth) on the composition and biomass of phytoplankton communities were assessed in 29 subtropical shallow lakes in Wuhan, China, during different seasons from December 2017 to November 2018. The results showed that phytoplankton in all 29 lakes was mainly composed of Cyanophyta, Chlorophyta, and Bacillariophyta. Phytoplankton abundance was highest in summer and lowest in winter. We analyzed the relative importance of the three groups of variables to the community composition of the phytoplankton by variance decomposition. The results showed that the three groups of environmental variables had the highest explanation rate (> 80%) for the composition of the phytoplankton community in summer and autumn, and the explanation rates in spring and winter were 42.1% and 39.8%, respectively. The water quality physicochemical parameters were the most important variables affecting the composition of phytoplankton communities, followed by land use in the watershed. Through generalized additive model and structural equation model analysis, we found that the land use and lake morphology had minimal direct impact on the Chl-a and cell density of phytoplankton, mainly by altering the TN, TP, turbidity, SD, DO, and EC, which indirectly affected phytoplankton. WT and nutrients were still the main predictors of phytoplankton abundance. Built-up land was the main source of nitrogen and phosphorus in lakes. Correlation analysis found that forest and grassland had positive impacts on reducing lake nitrogen and phosphorus contents. This showed that increasing grassland and forest in the watershed could reduce the pollutants entering the lake. Our findings will contribute to water quality management and pollution control for subtropical shallow lakes.

Selection and validation of appropriate reference genes for RT-qPCR analysis of flowering stages and different genotypes of Iris germanica L.

Iris germanica L. is a perennial herbaceous plant that has been widely cultivated worldwide and is popular for its elegant and vibrantly colorful flowers. Selection of appropriate reference genes is the prerequisite for accurate normalization of target gene expression by quantitative real-time PCR. However, to date, the most suitable reference genes for flowering stages have not been elucidated in I. germanica. In this study, eight candidate reference genes were examined for the normalization of RT-qPCR in three I. germanica cultivars, and their stability were evaluated by four different algorithms (GeNorm, NormFinder, BestKeeper, and Ref-finder). The results revealed that IgUBC and IgGAPDH were the most stable reference genes in '00246' and 'Elizabeth', and IgTUB and IgUBC showed stable expression in '2010200'. IgUBC and IgGAPDH were the most stable in all samples, while IgUBQ showed the least stability. Finally, to validate the reliability of the selected reference genes, the expression patterns of IgFT (Flowering Locus T gene) was analyzed and emphasized the importance of appropriate reference gene selection. This work presented the first systematic study of reference genes selection during flower bud development and provided guidance to research of the molecular mechanisms of flowering stages in I. germanica.